This invention relates to a test that determines the amount of glycol in water such as runway surface water, and more particularly, this invention relates to a method and apparatus for quickly determining the amount of glycol contained in water.
Because of the increasing amount of air travel, there is ever-increasing pressure to fly aircraft in the wintertime. Attempting to maintain winter schedules often results in aircraft departures during snow storms. Accumulation of snow on the wings and body of the craft can interfere with lift. Thus to prevent such accumulations, the aircraft is sprayed at a spray pad or departure gate with a de-icing material containing glycol. While a large portion of the glycol-based material can be contained at the spray pad, a portion of it gets carried onto the runway and finds its way to storm drains. However, release of glycol to the environment is severely restricted by environmental protection agencies. Thus, to prevent such releases, the runways can be cleaned to recover the de-icing liquid prior to its entering the storm drains. Often, prior to cleaning or after cleaning, it is necessary to know the amount of glycol in the surface water on the runway to determine if cleaning is necessary or if further cleaning should be performed to prevent release of the glycol. This requires a test that can be performed out on the runway for purposes of immediate decisions. Prior procedures for glycol determination have not permitted such determination without a great deal of time to run the analysis. That is, the procedures have reverted to laboratory conditions where the organic material is oxidized in a boiling mixture of chromic and sulfuric acid, for example, as described in Standard Methods for the Analysis of Water and Wastewater, 7th Ed., on the basis of chemical oxygen demand (COD). The methods described therein in are an "Open Reflux Method" procedure 5220B and a "Closed Reflux, Tetrimetric Method", procedure 5220C. Both methods are complicated and as a result are usually carried out in an equipped laboratory.
In the prior art, there are disclosed tests for the determination of glycols. For example, Canadian Patent 1,018,878 discloses a method for testing for the presence of glycol-based antifreeze in lubricating oils using pellets containing Na.sub.2 SO.sub.3, pararosaniline hydrochloride, NaHCO.sub.3, magnesium stearate and polyvinylpyrrolidone. Generally, in the test, an oil sample is combined with toluene. A sample of the toluene/oil mixture is then added to a H.sub.2 SO.sub.4 /KIO.sub.4 solution and after stirring, a pellet is added to this mixture. The amount of glycol present is indicated by color.
U.S. Pat. No. 3,635,677 discloses a procedure for the determination of glycol in oil. A sample of engine oil is added to an aqueous oxidizing solution and the mixture shaken and allowed to separate. A sample of the aqueous phase is added to a chromogenic aldehyde reagent adsorbed on a support media. The presence of glycol is observed by chromogenic determination.
U.S. Pat. No. 4,125,373 also discloses a method for determining the amount of trace ethylene glycol in oil.
However, none of these references provide for a quick determination of the amount of glycol in water. Further, these methods appear to require highly skilled technicians. Thus, it can seen that there is a great need for a quick test to determine the presence of glycol in water, such as surface water, in order that cleaning operations can be carried out efficiently.